Heretofore, portable bracing-type security door stops have been commercially available which have typically consisted of an elongated rod providing an upper door handle engaging end and an opposite floor engaging end which can be propped against the inner side of the door as an extra precautionary measure to preclude unauthorized entry therethrough in houses, businesses and particularly in other public places such as hotels and the like, where the normal security locks and the like might not be considered adequate. Of course, broom handles and other stick-like braces have been used for years in the home without much degree of success because of the lack of portability and difficulty in maintaining them in dependable bracing position since they are easily dislodged by even the slightest shaking movement of the door. An example of such a commercially available doorstop provides an elongated tubular rod which, while even though longitudinally adjustable, does not have sufficient holding capability to ensure it remains in place under even less than extreme situations. The upper door handle engaging end is somewhat blunt and only incorporates a rather shallow scallop or groove which requires wedging against the underside of the doorknob or other handle structure of the door which can be easily dislodged. Likewise, the opposite floor engaging end of the brace has a foot member connected to the rod by a complicated and costly ball and socket-type joint which would permit the rod to be swung away from the door in any direction from even the slightest jarring forces that might be applied to the outside of the door by a potential intruder. Furthermore, such unit has no way of accommodating a wide variety of floor surfaces to preclude slippage from a relatively soft carpet to the harder and slicker floor surfaces such as wood, slate, tile and the like. Further, none of such prior art devices afford any audible indication of a potential forced entry other than the usual relatively quiet attempted manipulation of the door knob or other handle device. Consequently, it is recognized that an improved security door stop could be provided having a greatly simplified structure providing an audible alarm system which is easily and conveniently installed on the door handle engaging member and which may be quickly and dependably oriented with a floor engaging foot member that is capable of accommodating a wide variety of floor surfaces. Accordingly, the present invention is intended to overcome the problems as set forth above.